random.h

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/*
 *  This file is a part of TiledArray.
 *  Copyright (C) 2013  Virginia Tech
 *
 *  This program is free software: you can redistribute it and/or modify
 *  it under the terms of the GNU General Public License as published by
 *  the Free Software Foundation, either version 3 of the License, or
 *  (at your option) any later version.
 *
 *  This program is distributed in the hope that it will be useful,
 *  but WITHOUT ANY WARRANTY; without even the implied warranty of
 *  MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
 *  GNU General Public License for more details.
 *
 *  You should have received a copy of the GNU General Public License
 *  along with this program.  If not, see <http://www.gnu.org/licenses/>.
 *
 */
 
#ifndef TILEDARRAY_RANDOM_H__INCLUDED
#define TILEDARRAY_RANDOM_H__INCLUDED
 
#include <complex> // for std::complex
#include <cstdlib> // for std::rand
#include <type_traits> // for true_type, false_type, and enable_if
 
namespace TiledArray::detail {
 
//------------------------------------------------------------------------------
//                            CanMakeRandom
//------------------------------------------------------------------------------
template<typename ValueType>
struct CanMakeRandom : std::false_type{};
 
template<>
struct CanMakeRandom<int> : std::true_type{};
 
template<>
struct CanMakeRandom<float> : std::true_type{};
 
template<>
struct CanMakeRandom<double> : std::true_type{};
 
template<>
struct CanMakeRandom<std::complex<float>> : std::true_type{};
 
template<>
struct CanMakeRandom<std::complex<double>> : std::true_type{};
 
template<typename ValueType>
static constexpr auto can_make_random_v = CanMakeRandom<ValueType>::value;
 
template<typename T>
using enable_if_can_make_random_t = std::enable_if_t<can_make_random_v<T>>;
 
//------------------------------------------------------------------------------
//                       MakeRandom
//------------------------------------------------------------------------------
 
template<typename ValueType>
struct MakeRandom {
  static ValueType generate_value() {
    return static_cast<ValueType>(std::rand() / RAND_MAX);
  }
};
 
template<typename ScalarType>
struct MakeRandom<std::complex<ScalarType>> {
 
  static auto generate_value() {
    const ScalarType real = MakeRandom<ScalarType>::generate_value();
    const ScalarType imag = MakeRandom<ScalarType>::generate_value();
    return std::complex<ScalarType>(real, imag);
  }
};
 
} // namespace TiledArray::detail
 
 
#endif